GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B1336: Device Power 3 Circuit Range

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+, Seat Adjuster Switch

B1420

1

--

--

Driver Seat Front Vertical Motor Down Control

B1336

1

1

--

Driver Seat Front Vertical Motor Up Control

B1336

1

1

--

Driver Seat Rear Vertical Motor Down Control

B1336

1

1

--

Driver Seat Rear Vertical Motor Up Control

B1336

1

1

--

Driver Seat Horizontal Motor Forward Control

B1336

1

1

--

Driver Seat Horizontal Motor Rearward Control

B1336

1

1

--

Driver Seat Recline Motor Forward Control

B1336

1

1

--

Driver Seat Recline Motor Rearward Control

B1336

1

1

--

1. Power seat inoperative

Circuit/System Description

Battery positive voltage is supplied at all times to the memory seat module (MSM) through the battery positive voltage circuit from the PWR SEATS circuit breaker located in the I/P fuse block. This voltage is used to power up the MSM and also to apply power to the seat motors when commanded On. The MSM applies battery voltage and ground to the seat motors through the motor control circuits. During memory recall and manual seat functions, the motor current is monitored through the motor control circuits by the MSM. When an overcurrent condition is detected by the MSM, it will disable the seat motors in order to prevent the internal MSM circuitry from damage. The MSM is grounded through the module ground circuit at G301.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

DTC B1336 will set when the MSM detects a short to ground on a motor control circuit for 100 milliseconds or more.

Actions Taken When the DTC Sets

    • The memory seat functions for the affected seat will be disabled.
    • The MSM will disable manual movements of the affected motor.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Diagnostic Aids

The memory seat module is also referred to as the Driver Position Module in certain scan tool menus.

Reference Information

Schematic Reference

Driver Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition ON, with a scan tool clear the current and history DTC.
  2. Determine which motor set the DTC by operating the seat motors listed below one at a time in both directions. Check for the DTC to set between each motor test.
  3. • Driver seat front vertical motor
    • Driver seat rear vertical motor
    • Driver seat horizontal motor
    • Driver seat recline motor
  4. Ignition OFF, disconnect the X3 harness connector at the MSM.
  5. Test for infinite resistance between the appropriate control circuits listed below and ground:
  6. • Seat horizontal motor forward control terminal N
    • Seat horizontal motor rearward control terminal S
    • Seat front vertical motor up control terminal A
    • Seat front vertical motor down control terminal M
    • Seat rear vertical motor up control terminal R
    • Seat rear vertical motor down control terminal P
    • Seat recline motor forward control terminal F
    • Seat recline motor rearward control terminal G
    If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate seat motor assembly or recline motor.
  7. Connect the X3 harness connector at the MSM and disconnect the appropriate X1 harness connector at the seat motor assembly or the seat recline motor.
  8. Connect a test lamp between the appropriate control circuits listed below:
  9. • Seat horizontal motor terminal A and terminal B
    • Seat front vertical motor terminal C and terminal D
    • Seat rear vertical motor terminal E and terminal F
    • Seat recline motor l terminal A and terminal B
  10. Ignition ON, command the appropriate motor in Forward/Rearward or UP/Down directions with a scan tool. The test lamp should turn ON when commanding the motor in the froward and rearward or up and down directions.
  11. If the test lamp remains OFF during either of the commands, test for a short to ground or an open/high resistance on the control circuits. If the circuits test normal, replace the MSM.
  12. If all circuits test normal, test or replace the appropriate seat motor assembly or recline motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Driver Seat Adjuster Replacement
    •  Control Module References for MSM replacement, setup, and programming